This invention relates to new and useful components assembled into laminated architectural products such as patio doors or other products typically used as barriers between the interior and exterior of a house or other building.
Doors and other architectural products that are exposed to the exterior of houses or other buildings are often constructed of unstable wood and therefore are subject to warping. The exterior surface of these products is often protected from the weather either by multiple liquid coatings, liquid coatings over a weather and/or moisture resistant overlay, or by a special cladding (typically aluminum or PVC). As an example, U.S. Pat. No. 5,116,446 illustrates a method of treating the exterior surface of an unstable wood core or substrate by applying a resin saturated overlay in a laminate that not only provides a smooth structure that virtually eliminates surface contamination, uneven surfaces, and telegraphing of surface imperfections, but also serves as a moisture barrier from the exterior. In many cases, this exterior surface protection increases the potential for warping because the interior surface, which serves more of an aesthetic function, often does not have equal protection against moisture penetration. The result is warpage of the product whenever there is a prolonged differential in humidity between the interior and exterior of a building. Warpage detracts from the appearance of the products and interferes with proper fitting and locking.
One solution for this problem is to seal the interior surface with the addition of a subsurface layer of a resin saturated overlay in a laminate that provides a moisture barrier. Quite often, however, this is not practical for desired aesthetics in the room, and it also may not be economically practical. Furthermore an overlay on the inner surface furthers the chance for error and one more possibility of delamination in the field.
The primary objective of this invention is to construct an architectural product using a unique family of adhesives that not only provides a bond between a wood core and a wide variety of interior or exterior overlays in a laminated construction, but also provides an effective barrier to moisture migration from surface to surface between the laminates and the wood core. The result is an engineered product manufactured primarily or wholly from wood that remains dimensionally stable in a wide variety of climates.
A more specific object is to provide a laminated architectural product having an inner or room facing laminate that is bonded to an unstable core by an adhesive that limits a moisture penetration therethrough of approximately 5 gms/sq. mtr/hr. or less, the adhesive being selected from the group consisting of polyurethane and polyolefin in hotmelt adhesives to form the strong adherence and effective moisture barrier. This laminate is used on the core in combination with a weather facing laminate or covering that likewise maintains at least such minimum moisture penetration.
In carrying out the objects of the invention the product of the invention comprises a body portion of the type that is constructed of a dimensionally unstable wood core. To prevent warping when the core is subjected to varied moisture conditions on its opposite sides, the core is protected with laminated structure moisture barriers on each of its interior and exterior sides. The moisture barrier on its inner side comprises the above mentioned adhesives that secure a laminate to the core and the moisture barrier on its outer side can comprise the herein mentioned adhesive or any other satisfactory type of moisture barrier that meets the requirement of limiting a moisture penetration of approximately 5 gms/sq.mtr/hr. or less.
The moisture barrier adhesive used with the invention, namely, the adhesives selected from the group consisting of polyurethane hotmelt adhesive and polyolefin hotmelt adhesive has not only been found to provide the desired moisture barrier for the inner and/or outer side laminates but also provide the desired adherence properties.
The invention will be better understood and additional objects and advantages will become apparent from the following description taken in connection with the accompanying drawings.